BGP is an external gateway protocol, meant to be used between different networks. It is the protocol used on the internet. It was built for reliability, scalability and control, not speed. Because of this, it behaves differently from the protocols covered thus far in this book.
BGP stands for Border Gateway Protocol.
BGP uses the concept of autonomous systems. An autonomous system is a group of networks under a common administration.
Autonomous systems run Interior Gateway Protocols (IGP) within the system. They run an Exterior Gateway Protocol (EGP) between them.
BGP version 4 is the only EGP currently in use.
BGP neighbors are called peers and must be statically configured.
BGP uses TCP port 179.
BGP is a path-vector protocol. ...